High‐Temperature Electromagnetic Wave Absorption Properties of ZnO/ZrSiO₄ Composite Ceramics

Abstract

Owing to the widespread presence of electromagnetic interferences, it is necessary to develop new materials with excellent high‐temperature electromagnetic wave (EM) absorption properties. In the present work, ZnO is infiltrated into porous ZrSiO4 substrates to form ZnO/ZrSiO4 composite ceramics using sol‐gel process. The doping of aluminum results in the improvement of electrical conductivity and the significant change in the morphology of ZnO. With the increase in environment temperature during measurement, the permittivity of the composite ceramics increases first and then decreases dramatically, which is attributed to the change in conductive loss. The electrical conductivity increases with increasing measurement temperature. However, the concentration of oxygen vacancies decreases under air atmosphere when the measurement temperature increases continuously, which results in the reduction in conductivity. Therefore, permittivities of the undoped and doped ceramics measured at 673 K are higher than the ones at the other temperatures. The composite ceramics maintain a relatively high EM absorption coefficient, low reflection coefficient (RC), and wide effective absorption bandwidth at environment temperatures up to 773 K. As a result, we conclude that the ZnO/ZrSiO4 composite ceramics exhibit a promising prospect as a kind of high‐temperature EM absorbing material.

Multiscale designed SiCf/Si3N4 composite for low and high frequency cooperative electromagnetic absorption

“…The temperature dependent RLs for both flat structure and crossing grooved meta‐structure were measured at six temperature spots from 25°C to 500°C (25, 100, 200, 300, 400, 500°C). To ensure the accuracy of measurement, a holding time of 30 mins was required for each set point temperature dependent data of permittivity and RL in the whole temperature range …”

“…To ensure the accuracy of measurement, a holding time of 30 mins was required for each set point temperature dependent data of permittivity and RL in the whole temperature range. 26…”

Microstructure and EMW absorption properties of CVI Si3N4–SiCN ceramics with BN interface annealed in N2 atmosphere

“…[1][2][3][4] Therefore, the researches on microwave absorbing materials have attracted considerable interests in recent years. [1][2][3][4] Therefore, the researches on microwave absorbing materials have attracted considerable interests in recent years.…”

“…Electromagnetic radiation has detrimental effects on device performance and the surrounding environment with the rapid development of electronic instruments and telecommunication technologies. [1][2][3][4] Therefore, the researches on microwave absorbing materials have attracted considerable interests in recent years. The most widely used high-temperature electromagnetic wave (EMW) absorbers are nanocarbon materials, [5][6][7] SiC grains or fibers 8,9 and SiCN-based ceramics, [10][11][12] which have low density, high environmental stability, and excellent electromagnetic wave attenuation characteristics.…”

Crystallization Mechanism of CVD Si3N4–SiCN Composite Ceramics Annealed in N2 Atmosphere and Their Excellent EMW Absorption Properties

“…W ITH the development of electronic technology, electromagnetic interference (EMI) has a severe influence on both military and civil fields. 1,2 Microwave-absorbing materials have attracted more and more attention because they can absorb microwaves effectively and convert electromagnetic energy into thermal energy or dissipate microwaves by interference. 3 Therefore, there is a great deal of interest in the selection of various microwave absorbents, the preparation methods and electromagnetic properties of materials.…”